参考答案

正确答案：A
解析：细节题。从短文中The first group goes to an area of the bone that needs repair．This group of cells produce the chemical that actually breaks down the bone tissue，and leaves a hole in it.可知第一组特殊细胞的功能是“产生能破坏骨组织，在骨组织中空留一个洞的化学物质”，A选项正确。